SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57948f2a025e1ecd0a3ea18645ad2f4253cf2a40566ebae9a62993f4d41db1fc' 
  AND token = 'mDXbq8epB7R5bO5fnIEutLWf5seBlRvz+FA4GhG1uOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}